01 - Preheat oven to 400°F. Slice the top off the head of garlic, drizzle with 1 teaspoon olive oil, wrap in foil, and arrange on a baking tray alongside the quartered tomatoes. Drizzle tomatoes with 1 tablespoon olive oil and season with salt and black pepper.
02 - Roast in the oven for 35 to 40 minutes until tomatoes are tender and garlic is golden and caramelized.
03 - While the vegetables roast, heat 1 tablespoon olive oil in a large pot over medium heat. Sauté the chopped onion for 5 to 7 minutes until translucent.
04 - Toss bread cubes with 2 tablespoons olive oil, dried Italian herbs, and salt. Spread evenly on a baking sheet and bake for 10 to 12 minutes, tossing once halfway through, until golden and crisp. Set aside.
05 - Squeeze roasted garlic cloves from their skins. Add the roasted tomatoes with their juices and garlic to the pot with onions. Stir in vegetable broth and simmer gently for 10 minutes.
06 - Stir in fresh basil leaves and sugar if using. Remove from heat.
07 - Use an immersion blender to purée until smooth. For an extra silky texture, strain through a fine mesh sieve.
08 - Stir in heavy cream or coconut milk if desired. Adjust seasoning with additional salt and pepper to taste.
09 - Ladle soup into bowls and top with prepared croutons and extra fresh basil leaves.